Improvement in blast-apparatus



BENJAM IN F. STU-RTEVANT, 'EST IRQXBURY, M ASSACHUSE TT Q.

Letters Patent 'No.:92,`490, dated July 13, 1869.

IMPROVEMENT IN BLAST-APPARATUS.

The Schedule referred to in these Letters Patent and making part of the same.

To all whom t'tl'nay concern Be it known that I, BENJAulN AF. STURrEvAN'r, of I of my invention suiicient to enable those skilled in the art to practise it.

In employing centrifugalA blowers, itis often an object to heat or to cool the air moved thereby, on its passage into or from the blower, and sometimes to cool the air before it enters, and to heat it after it leaves the blower, as in cases where very dry hot vair is needed.

The air, moved by the blower, and heated or cooled, or both cooled and heated, is under pressure, so that it can be conveyed and directed to any locality within reasonable limits, to be utilized in mechanical and man.- ufactiuing-operations, or for sanitary purposes.

In most cases where a blower is used, the power of a steam-engine is employed to drive it, and I propose to utilize the heat escaping with the exhaust-steam,l for heating the air acted upon by the blower. v As air is extremely mobile, and as centrifugal blowers are operated at highl velocities, and as the heat of the steam must be transmitted or conducted through metal, a heater or cooler, to be combined with a blower, must have peculiarities involved in my invention in order to be eii'ective in heating or cooling an air-ciu'rent moving 'at the'rate of speed usual in centrifugal blowers.

Figure 1, of the (hawings, is a section taken in the plane ofthe line s z, seen in Figure 2; which is`a section illustrating an embodiment of my invention, said sectionv beingtakeu in the plane ofthehnegljfy,iig.l.v f'

.The blower shown is one of my well-known construction, having a central inlet and a tangential outlet, to

either or both of which heaters or coolers, 'or one heater and one cooler, may be connected, by means of bolts, a, which have their heads coupled in the dovetailed groove 1),-surrounding the inlet-passage, or in a similar groove in the ring c, which is secured to the end of the blower-outlet, said bolts passing through the Ilange zl of the bonnet e, covering one tube-sheet, f, of the heater or cooler g.

The body of the cooler is preferably' made of metal which does not readily oxidize like iron, such as copper or brass, and the heads fj", and the tubes h, which are secured therein, should be made of such metal, of the minimum thickness suited for practical use, as said heads and tubes form the surfaces through which heat is conducted to the air-currents passing to or from the blower, or through which heat is abstracted from said currents. I

The heads ff are so thin that the tube-ends cannot be secured in the tube-sheets in the ordinary way;

Y hence, I ilange each hole therein, for yreception of the tube-ends,'and this enables me to eiectually secure the tube-ends to the tube-sheets by soldering or braz- The flanges ofthe tube-sheets f f aroundthe tubeends are denoted by t in the drawing.

The metal, j, forming thepeiiphery of the heater or cooler g, is preferably 'covered by a jacket, lc, to prevent radiation of heat when heating, or absorption of.

heat from the atmosphere when cooling air-currents passing through the tubes 71;

The space contained in the heater or cooler around the tubes h, and between the heads or tube-sheets f f yand the periphery' j,'is provided with passages, l l',

through which exhaust steam can be made to enter said space, and the water resulting from condensation of the steam can'pass oii, if the object is to heat the air moving through tubes h, while, if the object is to cool the air, frigoric mixtures, like ice or snow and salt, for example, are introduced around the tubes, or a current of cold wat r may be madeto till the space around the tubes tlowmgii through one opening-and out at the other.

The boimet e', like the honnete, expands from the size of the central air-passage, so s-to enclose the ends of all the tubes in the heater or cooler, and in order to retard the air-current in the tubes h, so as to give time forthe air passing through them to receive or to part with heat, the joint area of the tubes should considerably exceed the area ofthe main air-pipe and the area of the inlet and outlet of the blower.

It will be seen, that from the manner in which the heater or cooler is connected with the inlet or delivery of the blower, the whole body. of the heater or cooler can be turned to bring the passages l l into any convenient location for the attachment of exhaust-steam or other pipes to suit the requirements of special cases.

I claim an air-blast apparatus, consisting of the combination, with a rotary blower, of the heater or cooler,

- constructed and arranged for mutual operation together,

substantially as described. f

' BENJ. F. STURTEVANT.

lVitnesses:

FRANCIS GoULn, C. WARREN BROWN. 

